AEST to MST
-17hAEST
AESTSOURCEMST
MSTGreen rows indicate typical business hours (9 AM - 5 PM)
AEST and MST on the World Map
The map below highlights the AEST (Australian Eastern Standard Time) and MST (Mountain Standard Time) timezone regions across the globe.
AEST – Australian Eastern Standard Time
UTC+10:00Australian Eastern Standard Time (AEST) covers eastern Australia, 10 hours ahead of UTC.
- •Queensland does not observe daylight saving time, staying on AEST year-round.
- •Sydney and Melbourne switch to AEDT (UTC+11:00) in summer.
- •The Australian Securities Exchange (ASX) operates on AEST/AEDT.
- •AEST is 15 hours ahead of EST during winter.
MST – Mountain Standard Time
UTC-07:00Mountain Standard Time (MST) is the time zone for the Mountain region of North America, 7 hours behind UTC.
- •Arizona does not observe daylight saving time, staying on MST year-round.
- •The Navajo Nation in Arizona does observe DST, unlike the rest of the state.
- •Denver, the 'Mile High City', is the largest city fully in MST.
- •MST covers 6 US states entirely and parts of several others.
AEST to MST Time Difference – Complete Guide
AEST runs on Australian Eastern Standard Time (AEST) at UTC+10:00. MST runs on Mountain Standard Time (MST) at UTC-07:00. That puts AEST 17 hours behind MST — a difference of -17h at the current offsets.
In practice, when it is 9:00 AM in AEST it is 4:00 PM in MST on the previous day. Midnight in AEST is 7:00 AM in MST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
AEST to MST time conversion table
| AEST (AEST) | MST (MST) | Day |
|---|---|---|
| 12:00 AM | 7:00 AM | previous day |
| 6:00 AM | 1:00 PM | previous day |
| 7:00 AM | 2:00 PM | previous day |
| 8:00 AM | 3:00 PM | previous day |
| 9:00 AM | 4:00 PM | previous day |
| 12:00 PM | 7:00 PM | previous day |
| 3:00 PM | 10:00 PM | previous day |
| 5:00 PM | 12:00 AM | same day |
| 6:00 PM | 1:00 AM | same day |
| 9:00 PM | 4:00 AM | same day |
Why people convert AEST to MST time
- Scheduling a call from AEST to MST: a 10:00 AM start in AEST lands at 5:00 PM in MST the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -17h gap: AEST and MST have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in MST is 4:00 PM in AEST.
- Coordinating a AEST-based team with MST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM AEST" is unambiguous; "3 PM" across a -17h gap is not.
- With a -17h gap there is no shared 9-to-5 window, so alternate the early start: one week AEST takes the early slot, the next week MST does.
About AEST (Australian Eastern Standard Time)
Australian Eastern Standard Time (AEST) is used in the eastern states of Australia including New South Wales, Victoria, Queensland, Tasmania, and the ACT. During summer (October to April), NSW, VIC, TAS, and ACT switch to Australian Eastern Daylight Time (AEDT, UTC+11:00), while Queensland remains on AEST year-round.
About MST (Mountain Standard Time)
Mountain Standard Time (MST) covers the Rocky Mountain region of the United States and Canada. Arizona is notable for not observing daylight saving time, staying on MST year-round (except the Navajo Nation). The time zone includes major cities like Denver, Phoenix, Calgary, and Salt Lake City. During summer, most areas switch to Mountain Daylight Time (MDT, UTC-06:00).
Best time to call between AEST and MST
With a -17h offset there is no overlap inside a normal 9 AM – 5 PM day. MST opens at 9:00 AM MST, which is 4:00 PM in AEST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
AEST and MST have no shared working hours because of the -17h gap. Teams need to alternate early starts or rely on asynchronous handovers.
AEST is 17 hours behind MST (AEST UTC+10:00 → MST UTC-07:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
AEST
❄ Currently in Standard Time
Standard: UTC+10:00 · DST: UTC+11:00
Clocks spring forward on Sat, Oct 3, 2026
MST
☀ Currently in DST
Standard: UTC-07:00 · DST: UTC-06:00
Clocks fall back on Sun, Nov 1, 2026
⚠ These locations are currently in different DST states, so the time difference may change when clocks adjust.
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between AEST and MST?
AEST (AEST, UTC+10:00) is 17 hours behind MST (MST, UTC-07:00). The gap is currently -17h.
How do I convert AEST time to MST time?
Add -17h to AEST local time. For example, 9:00 AM in AEST is 4:00 PM in MST (previous day).
What time is it in MST right now?
MST uses MST at UTC-07:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -17h offset from AEST.
What is the best time to call MST from AEST?
There is no shared working-hours window because of the -17h gap. The closest option is 1:00 PM in AEST, which is 8:00 PM in MST.
Which is behind, AEST or MST?
AEST is 17 hours behind MST. When it is 12:00 PM in AEST it is 7:00 PM in MST.
Does daylight saving time affect the AEST–MST difference?
Neither zone observes daylight saving time, so the -17h offset between AEST and MST is fixed all year.
Which other cities share AEST's time zone?
AEST also covers Sydney, Melbourne, Brisbane, Canberra, Hobart, Gold Coast.
Which countries use AEST, AEST's zone?
AEST is used in Australia (NSW, VIC, QLD, TAS, ACT), Papua New Guinea.
Is there a day difference between AEST and MST?
Sometimes. The -17h gap is large enough that 8:00 PM or later in AEST already falls on the in MST.
What is the time difference between AEST and MST?
MST is -17h from AEST.
What timezone is AEST in?
AEST operates on its local timezone.
What timezone is MST in?
MST operates on its local timezone.
Which countries use AEST (Australian Eastern Standard Time)?
AEST is used in Australia (NSW, VIC, QLD, TAS, ACT), Papua New Guinea.
Does AEST observe daylight saving time?
Yes, AEST switches to AEDT during summer months.
What are some interesting facts about AEST?
Queensland does not observe daylight saving time, staying on AEST year-round. Sydney and Melbourne switch to AEDT (UTC+11:00) in summer.
Which cities are in the MST timezone?
Major cities in the MST timezone include Denver, Phoenix, Salt Lake City, Calgary, Edmonton, Albuquerque, El Paso, Tucson.
What is the UTC offset for MST?
Mountain Standard Time (MST) is at UTC-07:00. During daylight saving time, it shifts to MDT.
What should I know about the MST timezone?
Arizona does not observe daylight saving time, staying on MST year-round. The Navajo Nation in Arizona does observe DST, unlike the rest of the state.
When is it midnight in AEST, what time is it in MST?
When it is 12:00 AM (midnight) in AEST (AEST), it is -17h later in MST (MST).
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See every conversion from AEST →·See every conversion from MST →